OptiPhos® Plus CT Can Withstand Extreme Pelleting Conditions

Lode Nollet

OptiPhos® Plus is by far the most heat stable phytase on the market. In its granular form it has demonstrated to be heat stable up to 85 oC. For more extreme pelleting conditions, a coated version (OptiPhos® Plus CT) has been developed.

In some situations, feed is conditioned at temperatures above 85 oC for a normal length of time (30 - 90 seconds) before pelleting. There are other situations where feed is conditioned for longer (2 - 5 minutes) at temperatures up to 85 oC, but without pelleting afterwards. This process is known as 'hygienisation'. Aviagen recommends a conditioning time of 6 minutes at 85 - 90 oC followed by pelleting to hygienise the feed (where the main goal is to destroy pathogenic bacteria like Salmonella).

 Examples of situations where OptiPhos® Plus CT has demonstrated survival under these more severe pelleting conditions are detailed in this article. Use of a highly stable phytase like OptiPhos® Plus CT avoids the necessity of using phytase in its liquid form and applying it post-pelleting.

 

OptiPhos® Plus CT survives severe pelleting conditions

In a European field trial, breeder feeds were supplemented with 200 g/T of OptiPhos® Plus 5000 CT to reach the desired level of 1000 FTU/kg feed. The feed was heated to 84 oC for 4 minutes or to 88 oC for 6 minutes but not pelleted after conditioning ('hygienisation' of the breeder feed). It was concluded that OptiPhos® Plus CT survives prolonged hygienisation under these conditions (Figure 1). 

 

Figure 1. Recoveries of OptiPhos® Plus CT at prolonged hygienisation without pelleting

 

In a second study, broiler feed was supplemented with 200 g/T of OptiPhos® Plus 10000 CT to reach 2000 FTU/kg feed. The following treatments were applied before pelleting at 3.6 mm: 

  • Conditioning for 220 seconds at 75 oC
  • Conditioning for 220 seconds at 80 oC
  • Conditioning for 360 seconds at 80 oC
  • Conditioning for 220 seconds at 85 oC

It was demonstrated that OptiPhos® Plus CT survives prolonged conditioning followed by pelleting as recoveries were all above 80 % (Figure 2). 

 

Figure 2. Recoveries of OptiPhos® Plus CT at prolonged conditioning followed by pelleting

 

Even in situations where extrusion has been part of the feed processing, OptiPhos® Plus CT has shown its strong heat stability. A corn/soy broiler feed supplemented with OptiPhos® Plus CT to reach 1000 FTU/kg was run through an extruder by addition of 6-8% water to achieve a certain moisture content. The extrusion process was conducted at two different temperature settings (90 oC and 100 oC), whereafter the feed was forced through a 3 mm diameter die.

In this trial OptiPhos® Plus CT showed recoveries of 89% at 90 oC, while at 100 oC an acceptable 74% recovery was achieved (Figure 3). Assuming an overage in the product of 25%, the actual phytase concentration in the final feed after extrusion would be at the required level.

 

Figure 3. Recovery rates of OptiPhos® Plus CT in corn/soy broiler feed subjected to extrusion at different temperatures

 

Conclusion

As OptiPhos® Plus is renowned for its excellent pelleting stability, now OptiPhos® Plus CT opens extra perspectives when even more extreme temperatures are applied or when feed is treated for a longer time at elevated temperatures.

The use of OptiPhos® Plus CT creates a valid alternative for application of liquid enzymes post pelleting, which normally requires large investment in dosing- and post-pelleting liquid application systems.